| 摘要: | 本實驗主要利用噴霧熱烈解法來製作一系列不同比例之CuInZnS薄膜，並測量其光電化學性質，但由於CIZS薄膜同時為四種不同元素所組成，成分過於複雜，難以尋得具有最佳光電化學性質之比例，因此實驗主要分成兩部分開發，第一步部分為：優先製作出具有最佳光電化學性質之比例的CIS薄膜，而此部分已由本實驗是已畢業博士班學長楊凱輿學長完成，第二部分則為固定先前所製作得出之前驅物中，銅、銦、硫的比例，並在前驅物中加入不同比例的鋅，來探討在不同[Zn]/[In]比例下，其光電化學性質改變之情形。
實驗結果顯示，隨著鋅在前驅物中的比例增加，CIZS於XRD圖譜分析中皆可觀察到其主要的訊號皆有朝向高角度偏移的情形，因此證明有CuInS2-ZnS solid solution產生，且其能隙值也從1.45 eV改變至2.1 eV。而在光電化學性質中，在電壓為-0.752 V v.s. R.H.E.，電解液為0.5 M K2SO4(Ph=6.8)時，[Zn]/[In]=2.4 之CIZS薄膜其光電流能最高達到2.51mA/cm2 ，且從Mott–Schottky的測試結果可以發現，其導電性質並沒有因為鋅的加入而改變，均呈現p-type的導電性質。而[Zn]/[In]=2.4 之CIZS薄膜在外加偏壓-0.152 V v.s. R.H.E.的條件下，進行一小時的穩定性測試後，仍然具有90%的光電流表現，我們也利用測量CIZS薄膜在不同[Zn]/[In]比例下的光電轉換效率(IPCE)，以探討在改變紫外光可見光吸收波段後，CIZS薄膜在各個波長的光源下之光電轉換的情形。另外我們也同樣使用噴霧熱烈解法在CIZS薄膜的表面噴塗上一層n-type 的In2S3來進行表面改質，期望能夠藉此製作出具有CIZS/ In2S3 p-n juction的薄膜，以及透過在CIZS薄膜表面蒸鍍Pt來做為共觸媒的使用，進而達到提升其光電化學性質的效果，相較於未裝載Pt的CIZS薄膜，CIZS/Pt 薄膜的over potential明顯降低的許多，但CIZS/ In2S3 的薄膜測試結果則並未達到我們預期的效果，因此在後續電化學實驗中，我們也嘗試利用不同的方法來討論造成其結果的原因。;In this experiment, a series of different ratios of CuInZnS films were prepared by spray pyrolysis method, and their photoelectrochemical properties were measured. However, since CIZS films are composed of four different elements at the same time, the composition is too complicated and it is difficult to find the best photoelectrochemical properties, so experiments developed mainly divided into two parts, the first part : Preference is given to producing CIS films with the best photoelectrochemical properties, and this part has been completed by the graduated Ph.D., Yang Kaixuan. seniors . The second part is to fix the ratio of copper, indium and sulfur in the previous precursors, and to investigate the changes in photoelectrochemical properties at different [Zn]/[In] ratios.
The experimental results shows that with the increase of the proportion of zinc in the precursor, CIZS can be observed that the main signals are shifted to a high angle in the XRD pattern analysis, so it is proved that CuInS2-ZnS solid solution is produced, and its energy gap value also changed from 1.45 eV to 2.1 eV. In photoelectrochemical properties, the CIZS film with [Zn]/[In]=2.4 has a photocurrent density of up to 2.51 mA/cm2 at a voltage of -0.752 V vs RHE and an electrolyte of 0.5 M K2SO4 (Ph=6.8).From results of Mott-Schottky, it can be found that the conductive properties are not changed by the addition of zinc, and all exhibit p-type conductive properties. The CIZS film with [Zn]/[In]=2.4 has a 90% photocurrent performance after one hour of stability test under the applied bias voltage of -0.152 V vs RHE. The photoelectric conversion efficiency (IPCE) at different [Zn]/[In] ratios was used to investigate the photoelectricconversion of CIZS films under various wavelengths of light sources after changing the UV-vis absorption.
In addition, we also sprayed n-type In2S3 on the surface of the CIZS film by spray pyrolysis to do the surface modification. It is expected to produce a film with CIZS/In2S3 p-n juction and use Pt as a co-catalyst to improve the photoelectrochemical properties. Compared with the CIZS film without Pt, the over potential of the CIZS/Pt film is significantly reduced, However, the CIZS/In2S3 film test results did not achieve our expected , so in the subsequent electrochemical experiments, we also tried different methods to discuss the reasons. |
